[DavidKok]

I've been looking for alternative response structures to a strong 1♣ opening. One of the structures that stood out to me is John Montgomery's Revision Club structure:

Spoiler

1♣*-(P)-?

• 1♦ = Any hand not covered by the bids below, i.e. most balanced hands regardless of strength, (almost) any GF hand, weak hands without a suit of their own or with a 5-card minor suit.
  
• 1♥ = 5(+) hearts, 0-8 HCP, NF.
  
• 1♠ = 5(+) spades, 0-7 HCP, NF.
  
• 1NT = Exactly 4♠4♥, 0-7 HCP, NF.
  
• 2♣ = 6(+) clubs, ~0-5 HCP, NF.
  
• 2♦ = 6(+) diamonds, ~0-5 HCP, NF.
  
• 2♥ = At least 5♠5♥, ~3-7HCP, NF.
  
• 2♠ = 9(+) HCP, any 4441 shape.

The higher responses are not very important. He suggests a similar structure in competition, i.e.

Over (for example) 1♣*-(1♥)-?, where the interference promises a heart suit (and may promise something else, the defence is the same):

• Pass = 0-4 HCP, at most 4 spades.
  
• X = GF, no good bid (so (semi)balanced), 2(+) hearts (so that opener may convert to penalties easily).
  
• 1♠ = 5(+) spades, 0-7 HCP, NF.
  
• 1NT = ~6-8 HCP, NF natural.
  
• 2♣ = 6(+) clubs, ~5-7 HCP, NF.
  
• 2♦ = 6(+) diamonds, ~5-7 HCP, NF.
  
• 2♥ = GF takeout double (apparently called the 'Kantar Cue Bid'), showing shortness in their suit.
  
• 2♠ = (5)6(+) spades, 8+ HCP, GF.
  
• 2NT = A particular flavour of unusual, showing the highest of the unbid suits and another. At least 5-5. It is not stated but I presume this is GF.
  
• 3♣ = 6(+) clubs, GF.
  
• 3♦ = 6(+) diamonds, GF.

Note that this loses the option to give a takeout/negative double with less than GF values..

I'm interested in systems where weak or invitational hands can clarify some shape early. Most of the standard strong club structures I could find assign all of responders bids from 1♥ through 5♦ (or so) for GF hands, which to me seems awkward. This goes double in competition. Is it really so vital to establish a game force in competition at the 1- or 2-level? Transfers, or forcing bids starting at invitational strength, seem to do just fine in standard.

A second system I could find with some limited responses to a strong club was the Toad Club System:

Spoiler

1♣*-(P)-?

• 1♦ = 0-7 HCP, 'any' distribution (often (semi)balanced).
  
• 1♥ = 5(+) spades or clubs, 8+ HCP, GF.
  
• 1♠ = 5(+) hearts or diamonds, 8+ HCP, GF.
  
• 1NT = 12+ HCP, balanced. May have a 5cM.
  
• 2♣ = 6(+) clubs or diamonds, ~4-7 HCP. The notes don't discuss the continuations.
  
• 2♦ = 6(+) hearts, ~4-7 HCP.
  
• 2♥ = 6(+) spades, ~4-7 HCP.
  
• 2♠ = 8(+) HCP, any 4441 shape.
  
• 2NT through 3♥: 4-7 HCP, 7(+) cards in the suit above.

Are there other strong club systems (or Polish Club systems, or even response structures to a traditional strong two bid) that have responder describe shape immediately with weak hands? And in competition? In traditional Precision structures the 1♣ opening is quite likely to be a balanced minimum (e.g. 17-19 notrump), so playing a standard Rubensohl (or some other -ohl) scheme might work well. Instead the most common defence seems to be something like pass = 0-4, X = 5-7, bidding = 8+ GF with a real suit (optionally through a transfer). It seems strange to me to put so much emphasis on creating a game force, and so little on shape bidding with the most frequent hand types.

P.S.: The Revision Club uses a highly non-standard notrump ladder, so that the 1♣ opening is 16+ unbal or 21+ bal. This means that in that system in particular opener is extremely likely to have an unbalanced hand. It is a bit ironic that, of all strong club systems, this one in particular uses shape-showing bids for intermediate and weak hands.
P.P.S.: I suspect at least part of the motivation is that a game force is a requirement for relay bidding, so that it makes for more comfortable system design to have a lot of coded relay-based GF initial bids. I'm interested in the other extreme - what if we ditch the relay and prepare ourselves against interference as much as possible, even if this comes at the cost of some definition on slam hands.

[foobar]

DavidKok, on 2023-January-24, 10:42, said:

I've been looking for alternative response structures to a strong 1♣ opening. One of the structures that stood out to me is John Montgomery's Revision Club structure:
...
I'm interested in systems where weak or invitational hands can clarify some shape early. Most of the standard strong club structures I could find assign all of responders bids from 1♥ through 5♦ (or so) for GF hands, which to me seems awkward. This goes double in competition. Is it really so vital to establish a game force in competition at the 1- or 2-level? Transfers, or forcing bids starting at invitational strength, seem to do just fine in standard.
...
Are there other strong club systems (or Polish Club systems, or even response structures to a traditional strong two bid) that have responder describe shape immediately with weak hands?

Have you taken a peek at awm's IMPrecision?

Off the top of my head, the response structure is as follows, and the premise is that there's no immediate GF (except possibly some outliers).

...1♦: Super weak, or really strong (7+ QPs), or GF balanced hands that wish to retain control
...1♥: 4+ spades, 2-6 QPs
...1♠: Balanced without 4♠, or other hand types, 2-6 QPs
...1N: 5+♥ single-suited, OR (5+♥+4♣) OR (5+♥+4+♦), 2-6 QPs
...2C: ♣ or minors, reversed, 2-6 QPs
...2♦: 5+♣ + 4+♥, 2-6 QPs
...2♥+: Others

The Moscito responses with 1♦ GF and SP-responses are another option, but personally I never really cared about it (especially the 1♠ DN, but YMMV).

[DavidKok]

Thank you! I have system notes on both of these, they slipped my mind (Moscito in particular - I confused it with Terrorist Moscito, which uses a negative 1♦ response). IMPrecision sounds especially interesting, combining not-GF responses with relay methods.

[DavidKok]

I've looked through these notes and had some ideas:

• The IMprecision responses are based on symmetric relay, and (seem to) contain both the semi-positive hands (approximately 5-7 HCP) and the minimum game forcing ones (approximately 8-11 HCP). However, opener can only initiate a (GF) relay when they are prepared to go to game opposite the minimum in the range, i.e. has a ~20+ or so. Most of the non-relay answers are pass/correct, with some NF natural bids. I wonder how frequently you get to relay, and whether that's the best way to go with a generic game force.
  
• In doing the above IMprecision seems to give up on MAFIA (especially with exactly 4♥, but also with 4♠5(+)♥ 'reversers'). To facilitate the symmetric relay a lot of hands have to show spades regardless of their heart holding, or bunch heart-holding hands in with other hand types to save space.
  
• The wide® range of responses, i.e. approximately 5-11 (really 2-6 relay points where A=3, K=2, Q=1) might make cooperative bidding more difficult when opener isn't prepared to force to game. From my reading this seems like both the most frequent rebid (most 16+ hands aren't also 20+ hands) and the weakest part of the system.
  
• The IMprecision answers to interference seem not too great to me. As lots of relay systems do it has some extra uses if the opponents double or bid 1♦ over 1♣, they play system on over 1♣*-(1♥) regardless of meaning, and just give up when the bad guys bid 1♠ or up. Pages 2-10 explain the relay system and pages 10-11 explain how to go from there. Meanwhile the entire defence against interference fits on two pages (12 and the first half of 13). They have a non-GF takeout double (showing 5(+)) and transfers at the 2-level without clarifying the strength of these transfers, with pass showing approximately 0-8 and jump transfers showing 4-7 constructive non-GF preempts. The defence to 1♣*-(p)-1♦*-(1♠ or up); ? is literally the two lines "systems are off, revert to natural bidding. Doubles are takeout oriented and lebensohl-type methods apply to distinguish responder’s weak hands from the game force hands."
  
• I don't understand the Moscito structure yet. It seems focused on using coded answers so that both opener and responder may use a similar relay scheme, depending on who skips the cheapest bid first. There is great emphasis on using the step over every bid as a relay. Most of the bids resemble two-under transfers with specific two-suiters thrown in (first step: relay, second step: pass or correct). I think this is an interesting structure but hate not bidding long major suits immediately. It might also wreak havoc with constructive bidding - presumably you play ParadoX raises over these bids? The 1♠ negative is also not ideal.

Some other general points:

• In a MAFIA structure (which I think is a good idea) it makes sense to have 1♦, 1♥, 1♠ and maybe even 1NT responses to 1♣ either show or deny specific major suit holdings (within a certain strength range). All of these risk wrongsiding the contract, especially since opener may be unbalanced with the other major (e.g. something simple like swapping 1♥ and 1♠ doesn't solve this). I'm not sure how big of a deal this is.
  
• Trying to stop on the 1-level opposite a semi-positive seems near worthless so it's fine to make all these bids forcing (but not necessarily GF). My main question is how to allocate different major-suit holdings to different cheap bids. So far I think the IMprecision structure is best at this, showing spades often and zooming with 5(+) hearts hands. The Revision structure is also impressive - simple and effective.
  
• Since I'm not aiming to have a full shape-showing relay anyway I think I can get away with using my own classification of hand types. So far I think I'd like to have different bidding plans available for the following:
  • (semi)balanced with a 4cM.
    
  • (semi)balanced without a 4cM.
    
  • Hands with one major suit (5(+) in one M, 3(-) in the other, may have anything in the minors).
    
  • Hands with both major suits (at least 5-4 either way).
    
  • Three-suited hands without a 5cM (this implies one or both 4cM).
    
  • Hands with a long minor suit (at least 6(+), 6322 hands can be treated as semibalanced).
    
  • Hands with both minors (at least 54 either way).
  MAFIA means putting a lot of these together on the first round to show the major (possibly with artificial bids for hands with both majors), which I think is promising. That leaves the higher jumps for very specific hand types without great major suit support.

[awm]

Part of the design of IMPrecision is based on the belief that relay is not the best way to bid hands with 25-26 hcp combined and no great fit. The issue is that things like location of values and right-siding 3NT become much more important in auctions to pick the right game, whereas relay systems typically resolve this kind of thing quite late (often past the game level). Relays are great for slam bidding but if you don't have the values to look for slam, natural is often better. The combination of "semi positive or min GF" handles the vast majority of responder hands, puts us ahead if opponents bid in 4th seat, and still lets us relay when we're in the slam zone or find a big fit right away.

As far as competitive bidding, I think the use of double as "5-7 any hand" that seems to be popular among Precision players is quite atrocious. You often have no idea how to continue the auction, whereas shape-showing bids and doubles are much more helpful than just having an estimate of total points. We obviously could've come up with something more complex (and slightly better), but given the huge variety in defensive methods over strong club it seemed better to have something simple and less prone to misunderstandings when the opponents pull out some weird defense we've never seen before.

[DavidKok]

Thank you for the response! I fully agree with that comment on priorities in the game zone (rather than slam zone), and I'd like to go a step further and ignore relay in full. This will sacrifice some amount of accuracy in slam bidding, but I suspect not that much. In return it frees the need to have the initial responses be compatible with a(ny) relay system, so that I can incorporate principles such as MAFIA. Don't the multiple bids without an anchor suit expose you to interference? I'm trying to get ahead of exactly the auctions like 1♣*-(P)-1♠*-(2♠) where we might have trouble finding a 4-4 or 5-3 heart fit without safety at the 3-level.

I'm worried that the semipositive + positive range is too wide. 4-11 or 5-11 is still massive. I've just run a little simulation, and on the auction 1♣*-(P)-? I think responder will have 4-7 HCP about 34% of the time, and 8-11 HCP about 35% of the time. I like the concept but am curious about the choice of ranges. Why not, for example, 6-11 for the immediate responses, 0-5 as a negative (upgrade with good shape) and 12+ as a super-positive?

I'm rather interested in the defence outlined in the Revision Club system, although I think it would improve by using transfers (e.g. starting at 1NT, or at the current bid with 2-level interference) and making the double not GF.

[awm]

The idea is that the immediate responses that are not “super positive” are unlikely to produce slam opposite a minimum strong club. 6-7RP seems like the right dividing line here. Of course if there is a big fit things can change.

For the lower end, we don’t like giving a double negative with an ace, because this is a pretty big asset for slam when opener is super strong and we don’t really like slam auctions that start with a double negative. If an ace and out is semi-positive then probably a king plus a queen should be also.

These ranges also match standard bidding pretty well, where 5 HCP is about the minimum to respond and 12 is often game force.

It’s interesting that you seem to love MAFIA and yet are so worried about finding fits after interference! I’d expect to do much better with a method where I show five card suits rather than possibly canapé four carders! Yes it’s true that the 1♠ response might hide a four card heart suit, but against that we are way ahead on 1nt responses (FIVE hearts) and 2♦ (showing BOTH suits) compared to just showing 4+ hearts.

[DavidKok]

There are lots of methods to find fits after responder has shown a 4(+) major, e.g. support doubles. If I understand correctly the 1♥ response showing 4(+) spades may have (significantly) longer hearts, i.e. with 4, 5, 6 or even longer hearts the 4-card spade suit takes priority? I'm not extremely concerned with minor suit fits - as you say this is about game auctions, not slam auctions. So showing the major suit with a major-minor canape hand is, in my opinion, not a downside but an upside.

My goal is to make it so that on the majority of auctions 1♣*-(P)-1/2X-(1/2/3Y); ? opener has a good chance of estimating the degree of fit in the majors. If partner already showed or denied one (or both) majors that can help drastically cut the options from the most likely games 3NT, 4♥ and 4♠. If many unbalanced hands will open 1♣ it is also valuable to be able to assess that the hand is a misfit. MAFIA helps protect from interference in the majors especially, which in turn means there's more safety in opening 1♣ with shortness in a major. At least, that's the idea (based on a Revision Club).

That being said I do like the idea of unpacking the hearts hands immediately, or attempting to distinguish between a 4cM and a 5(+)cM. A generic "4+ in the suit bid, may be canape, best of luck" response at the 1-level seems far from optimal.

Is one ace really so difficult to find on 1♣-1♦ which later shows a double negative? Responding with the same range of hands as standard sounds like a high risk - the shape-agnostic strong club puts you behind the field, if partner now makes a 'similar-range-to-standard' response isn't it hard to catch up?

[Kungsgeten]

Since you asked about showing shape immediately after a strong 2♣ opening: Transfer responses is an option. Usually in those schemes the 2♦ response is two-way though: either 4+♥ or a waiting bid not suitable for other responses.

There are several ways to play transfers over 2♣. Here's one attempt I came up with: http://snortingmarad...clubs18_19.html
This one has a lot of focus on finding playable part scores since 18-19 NT is included in 2♣. If your 2♣ is something like 22+ then you probably want to change some things.

[straube]

My system notes are based on IMPrecision.

Since you're concerned about 4S/5H you could tweak as I've done...

1H-all 3-suited with spades
2H-4S/5+H 2-suited
2S-3-suited short spades
3C-45(40)

Strongly recommend IMPrecision. And its interference notes and continuations. Also recommend Adam and Sieong's NT structure and their double-barreled major suit invites.

[DavidKok]

I've been playing around with the IMprecision structure a bit, trying to get more majors in there. I like the above suggestion to split out 4S/5(+)H, but I don't love having to bid 1♠ with a hand with long diamonds (with or without a 4c♥) as well as with balanced hands. Currently I'm thinking of something like:

• 1♦ - negative or super-positive (all other bids are in between).
  
• 1♥ - 4(+) spades, 4(-) hearts.
  
• 1♠ - Balanced with 3(-) spades and 4(-) hearts (so no 5♥332). Treat 22(54) as balanced. Optionally also treat (32)(62) or 33(61) as balanced with a suitable hand, or even 34(51).
  
• 1NT - 5(+) hearts, 3(-) spades.
  
• 2♣ - 5(+) clubs without a 4cM or (31)54.
  
• 2♦ - 4♥, 5(+)m, not 44(50).
  
• 2♥ - 5(+)♥, 4(+)♠.
  
• 2♠ - 1444.
  
• 2NT and up: zoom with 6(+) diamonds, no 4cM.

There are multiple parts of this idea that I don't like. Folding (31)54 hands into the 2♣ bid is ugly (but I dislike bidding them at 2♠+ levels or systemically folding them into 1♠ even more). Reserving a whole bid for 1=4=4=4 hands is a waste of space. Unpacking the 6(+) diamonds hands at such a high level means they have to be GF, so the semi-positive hands don't have a good bid (this also goes for the 1=4=4=4 hands). The ambiguous minor in the 2♦ answer is less than ideal, maybe that is too high a price to pay to show a 4 card heart suit.
There is some good news too though. The percentages of each of these bids on the auction 1♣*-(P)-? are great - I chose the meaning based on the room I would want to expand the hand types, but (other than the 1=4=4=4 hand) they happened to sort themselves by frequency. Most of the bids leave room to make opener declarer (maybe I should swap 2C/2D/2H around a bit to improve that - e.g put the 4♥5m response in 2♥). There is potentially room to include some super-positives if I should want, taking some strain off of 1♦ (by far the most common and least descriptive answer, going by IMprecision relay points).

As a more general thought - since all of these are forcing (each bid contains some amount of GF hands), how viable is it to include some of the super-positives? Especially on the bids showing lots of shape information at once would it not be possible to make them unlimited (or split range) and bid on over an eventual signoff? Standard bidding does this all the time, making forcing shape-showing bids on GF, invitational and sometimes even weak hands without a care.

Edit: after thinking about it some more I think it might be better to rearrange the 2(+)-level responses a bit. Something like:

• 1♦ - negative or super-positive (all other bids are in between).
  
• 1♥ - 4(+) spades, 4(-) hearts.
  
• 1♠ - Balanced with 3(-) spades and 4(-) hearts (so no 5♥332). You may treat semibalanced hand types as balanced at your own discretion (i.e. 6m322, 24(52), 34(51), 22(54) etc.).
  
• 1NT - 5(+) hearts, 3(-) spades.
  
• 2♣ - 4♥5(+)m or 1444
  
• 2♦ - 5(+)♥, 4(+)♠.
  
• 2♥ -
  
• 2♠ - Both minors, (54) or longer (in either direction), no 4cM.
  
• 2NT - 6(+) clubs, no 4cM.
  
• 3♣ - 6(+) diamonds, no 4cM.

Optionally the 2♣ bid could be split by minor, adding the 1444 hand type to either call (the cheapest, or 'better minor', or 'you decide').

[straube]

Both of these ideas are bad. Just to illustrate, 1C-2S as both minors leaves you terribly placed without a fit. Presumably opener's 2N rebid is a relay ask when it needs to be a misfit. What's opener to do with 4522 minimum? Hope not to arrive in a 4-2 fit?

In short, you need to be thinking about how to land in part scores and your continuations would be nightmarish.

1C-2S as 3-suited short spades is not so bad considering 2N rebid by opener is a minimum misfit and 3C as GF relay leaves 4 steps for the four possible hand patterns. Awm would probably argue that his original use of 3-suited short club is better because 2N is misfit and 3C as GF relay doesn't have the problem that mine does in that clubs are a likely place to play with 1444 but not opposite 4441.

It's hard to get around 1C-1S, 1N being NF and 1C-2S, 2N being NF if 1S or 2S are semipositives.

Recommend you study IMprecision a bit more before you tinker. Understand the continuations. If you put too many frequencies into a first response, you will have trouble.

Ask Adam questions. Good luck.

[foobar]

DavidKok, on 2023-January-27, 18:08, said:

I've been playing around with the IMprecision structure a bit, trying to get more majors in there. I like the above suggestion to split out 4S/5(+)H, but I don't love having to bid 1♠ with a hand with long diamonds (with or without a 4c♥) as well as with balanced hands. Currently I'm thinking of something like:

[list]
[*]1♦ - negative or super-positive (all other bids are in between).
[*]1♥ - 4(+) spades, 4(-) hearts.
[*]1♠ - Balanced with 3(-) spades and 4(-) hearts (so no 5♥332). Treat 22(54) as balanced. Optionally also treat (32)(62) or 33(61) as balanced with a suitable hand, or even 34(51).

As straube noted, it's difficult to improve upon the IMPrecision structure without a significant downside elsewhere. Tweaks like factoring out the hands with ♥+♠ just shuffle the order, so it's a matter of preference, but anything else represents a structure that's sub-optimal when compared to the original.

[DavidKok]

I've tinkered with this idea some more and ended up with a structure that I think is very comfortable. Where traditional relay systems make responder establish a GF immediately IMPrecision somewhat inverts this, letting responder make positive answers with 2-6 RP and putting the onus on opener to establish a GF opposite that range. The cheapest relay (1♣-1♥; 1♠) is not forcing to game, but all other relays, 1♣-1♠; 2♣, 1♣-1NT; 2♣, 1♣-2♣; 2♦ etc. are.
I think this is a downside. Opener has 16-19 HCP approximately 80% of the time (my simulation claims 80.5% on the IMprecision auctions 1♣-(P)-[1♥-through-3NT]), but e.g. conditioning on no interference depends on the methods the opponents use. I'd say anywhere between 70% and 90% is consistent with this simulation). The figure for 16-18 HCP is 67.3%. By contrast, responder has 0-4 ~18%, 5-7 ~29% and 8+ ~53%. Ideally I would like to be able to relay whenever either opener's hand is good enough to force the bidding to a higher level (i.e. the chance of 'Zooming out of control' is very low) or when, opposite a minimum, responder's hand is strong enough to unilaterally force to game anyway. This way we get the traditional relays of 8(+) opposite 16-19 as well as the semipositive relays of 19+ opposite 5-7. Furthermore, since responder's call is shape-showing on semipositive and stronger hands, opener is in a good position to evaluate their hand (in particular, upgrade with a fit or fitting values).

The main idea to achieve this is what I call a 'strength handshake'. Opposite most responses opener's cheapest rebid is doubt-showing, usually a (semi)balanced minimum that isn't worth an upgrade in light of the suit shown. The second step instead is the relay (usually, but not always, GF), while the third step and higher are (mostly natural) calls. Most hands with tolerance for partner's suit(s) can make the waiting bid even with a minimum, so the third step and up can be very descriptive. Opposite the doubt-showing bid responder can instead give the relay answer anyway with an 8(+) hand, while the 5-7 hands can start looking for a side suit for or a partscore (or can sometimes even pass the first step).

The basic structure is:
1♦ - weak (~0-4 any) or [hearts but not spades, not BAL and not a three-suiter, may have a longer minor]
1♥ - [spades but not hearts, not BAL and not a three-suiter, may have a longer minor]
1♠ - BAL (split range, I think 5-9 or 13+ might work well?) or [diamonds, no 4cM, not BAL, not longer clubs and not a three-suiter]
1NT - clubs, no 4cM, not BAL, not longer diamonds and not a three-suiter
2♣ - (54)+ either way in the majors, not a three-suiter (I find this part a bit awkward - if I pick up (say) a 5=4=0=4 I'd like to show both majors first and the clubs as an afterthought)
2♦ - any three-suiter (this is probably the worst bid of the system, if partner holds a good 16-count with length opposite our shortness we will likely end in 2NT)
2♥ - at least 55 in the minors
2♠ and up: 10-12 BAL (filling in the gap from 1♠)
Note that showing a BAL hand takes preference over showing any particular suit.

There are some costs. The 2♣ (54) bid doesn't have enough space for this handshake if I don't want to go +1 on all these sequences, so instead I've done away with it there. Thankfully it is almost always correct to play 2M opposite at least (54) in the majors and weak, so 2♦ relay (not GF), 2♥ through 3♦ as descriptive and certain flavours of to play or pass/correct seems fine. I also go +1 on all three-suited hands, which thankfully are rare (~4.3%). I've been toying with using a non-symmetric scheme for three-suiters to regain most of that +1, but it's probably a terrible idea since it won't come up often. Thankfully everything else is at +0, i.e. meets the entry points of symmetric relay shape clarification structures. Lastly I'm losing some definition on, say, 18-19 opposite 0-4 hands, where standard systems might be able to bid 1♣-1♦; 1M (longest major) and start describing the hand, but I need to cater to the 5-7 Hearts hands as well. Thankfully my Hearts hands have sufficiently narrow definition, and 0-4 is infrequent enough, that I can split the two. Ironically I think this would be unplayable if the 'weak' range was 0-7, which would overload 1♦ far too much if it also had some positive hands.

Any and all feedback is very welcome. Writing up the full system would take a lot of time so I'll first pore it over a bit more and see if I want to make any changes, but I'm very excited about this.

[straube]

IMPrecision in a nutshell...

.....1C-strong
..........1D-very weak or very strong
...............opener describes, responder is captain
..........etc-GI or light GF
...............opener relays with fit or extras
...............opener suggests part score or invites without

DavidKok, on 2023-February-10, 13:49, said:

The basic structure is:
1♦ - weak (~0-4 any) or [hearts but not spades, not BAL and not a three-suiter, may have a longer minor]
1♥ - [spades but not hearts, not BAL and not a three-suiter, may have a longer minor]
1♠ - BAL (split range, I think 5-9 or 13+ might work well?) or [diamonds, no 4cM, not BAL, not longer clubs and not a three-suiter]
1NT - clubs, no 4cM, not BAL, not longer diamonds and not a three-suiter
2♣ - (54)+ either way in the majors, not a three-suiter (I find this part a bit awkward - if I pick up (say) a 5=4=0=4 I'd like to show both majors first and the clubs as an afterthought)
2♦ - any three-suiter (this is probably the worst bid of the system, if partner holds a good 16-count with length opposite our shortness we will likely end in 2NT)
2♥ - at least 55 in the minors
2♠ and up: 10-12 BAL (filling in the gap from 1♠)
Note that showing a BAL hand takes preference over showing any particular suit.


Any and all feedback is very welcome. Writing up the full system would take a lot of time so I'll first pore it over a bit more and see if I want to make any changes, but I'm very excited about this.

This...

1C-strong
.....1D-0-4 or hearts
..........opener describes as if 0-4 (as for IMPrecision), but can't show a heart fit since one may not exist. This not only means this information is wasted but ..........opener can't frequently relay responder's heart hands
.....1H-spades but not hearts, not bal or 3-suited, 5+
..........GF requires fit or extras (as does IMPrecision)
..........sign off with minimums
...............responder has a hard time relaying opener's shape when responder has GF values
.....1S-bal, split range, loses all 5-7 bal with spades compared to IMPrecision
..........GF with extras
..........sign off with minimums
...............responder with GF balance will be unable to relay for opener's complete shape (which can be done with IMPrecision)

[DavidKok]

That's not opener's rebid structure, though I'm interested in this version you present! Do you have more notes on it?

[straube]

No I don't. I think your responses to 1C will have difficult continuations starting with opener's rebid. I think you should learn IMPrecision first and then tinker with it if you can.